Light Dispersion

Aim : To investigate light dispersion by a prism.

Apparatus : Prism, white screen, light projector.

Method : 

( Note : it is advisable to cary out tis activity in a dark surroundings )
1. apparatus as shown in the figure 1.
2. a beam of white light is directed to the prism.
3. the prism is turned slowly until a band of colours is formed on the white screen.
4. the type n order of colours tht appear on da white screen is observed.
5. another identical prism is placed inversly behind the 1st prism, shown in figure 2.
6. the chgs of the spectrum on da screen r observed n drawn.

Observation:

1. a spectrum of visible light is seen on the screen.
red, orange, yellow, green, blue, indigo, violet
2. when a 2nd prism is placed inversly, the 7 colours r recombined to form a beam of white light again.



Conclution : A spectrum of colours is obtained frm the dispersion of white light through a prism. This is shown tht a white light consists of a spectrum of 7 colours.